Automatic clear sign printing



Oct. 13, 1953 4 H. L. PITMAN AUTOMATIC CLEAR SIGN PRINTING MECHANISM 5Sheets$heet 1 Filed Aug. 20, 1948 INVENTOR. HENRY L.P/TMAN ATTORNEY Oct.13, 1953 H. L. PITMAN AUTOMATIC CLEAR SIGN PRINTING MECHANISM 5Sheets-Sheet 2 Filed Aug. 20, 1948 s. Q L

1953 H. L. PITMAN AUTOMATIC CLEAR SIGN PRINTING MECHANISM 5 Sheets-Sheet3 Filed Aug. 20, 1948 \EECEC CEE Oct. 13, 1953 H. L. PITMAN AUTOMATICCLEAR SIGN PRINTING MECHANISM 5 Sheets-Sheet 4 Filed Aug. 20, 1948INVENTOR HENRY L. P/TMA/V BY 4 7% g wmmy 0d. 13, 1953 4 P|TMAN 2,655,311

AUTOMATIC CLEAR SIGN PRINTING MECHANISM Filed Aug. 20, 1948 5Sheets-Sheet 5 INVENTOR. HENRY L. P/TMAN Patented Oct. 13, 1953AUTOMATIC CLEAR SIGN PRINTING MECHANISM Henry L. Pitman, Melbourne,Fla., assignor to Underwood Corporation, New York, N. Y., a

corporation of Delaware Application August 20, 1948, Serial No. 45,372

12 Claims. I

This invention relates to combined typewriting and computing machinesand more particularly to machines wherein a single keyboard is employed,such as found on ordinary typewriters.

Machines of the type with which this invention is particularly concernedcomprise a computing base surmounted by a typewriter cooperatingtherewith. Within the base are normally contained a plurality ofregisters located in lateral alignment across the front thereof. Forrunning amounts into the wheels of the registers, there is provided aset of differential operator bars for each register.

The typewriter carriage is provided with a plurality of column unitsextending horizontally from the rear thereof, and as the carriage movesinto a computing zone corresponding to a column on the work sheet, oneof the column units, which may carry a plurality of dogs, depresses avertically extending plate, thereby selecting one of the registers foroperation. If the column unit carries more than one register selectingdog, then, of course, more than one register will be selected foroperation.

The differential operator bars which actuate the wheels of the registersare provided with indexing pins which are set in accordance with thedepression of numeral keys of the typewriter. When a numeral key isdepressed, the digit represented by said key is printed and the digitvalue is also indexed in one of the differential operator bars. Machinesof the character with which this invention is concerned are normallyprovided with a continuously operating power source and a one-revolutionclutch which, when engaged, connects a cycling general operator to theconstantly rotating power source. After all of the digits of an amounthave been selected, the one-revolution clutch is engaged, therebycycling the machine and running the selected and indexed amounts intothe wheels of the selected register or registers.

With machines of the type with which this invention is concerned, it ispossible to automatically print totals. That is to say, after one ormore amounts have been entered into a register, the amount then standingin the wheels of the register may be automatically read out and printed.For accomplishing this purpose, a set of total reading feelers isprovided for each registe and each register wheel is provided with aspiral arrangement of stops. When it is desired to print a total, theset of feelers is released and the individual feelers of the set moveforward into engagement with the stops, the amount of for- 2 wardmovement being determined by the particular digits standing in thewheels. These different forward positions of the feelers are thenemployed in selecting the amount to be printed.

The machine is also provided with a fugitiveone mechanism, making itcapable of recording and printing true overdrafts as well as truepositive amounts.

When a total is automatically read out of a register and printed, theamount standing in the register is indexed in the differential operatorbars for said register, and during the subsequent cycle of the machine,which always follows a total printing operation, the register moves toits subtractive position and the indexed amount is subtracted out of theregister thereby leaving the register clear.

The general form of the machine, as set forth above, is well known andis more particularly described in my prior Patent No. 2,372,681. Alsodescribed and shown in said patent is a mechanism whereby a star orother indicating symbol is automatically printed following a totaltaking operation if the register is properly cleared. In said patent, astar is only printed when a register is cleared as a result of a totaltaking operation.

It has been found desirable to print a star or other clear sign incertain columns wherein a register is cleared by an operation other thana total taking operation. For example, in certain bookkeeping setups, aProof column is provided, and when an amount is typed in the usual OldBalance column, said amount is run into at least two registers one ofwhich is a proof register. After the operator has entered theappropriate Debits and Credits and the machine has automatically printedthe new balance, the carriage is tabulated to the Proof column where theoperator again copies the old balance. At this carriage position, theproof register is again selected, but this time it is selectedsubtractively so that during the cycle following the typing of the oldbalance, the amount is run into the register subtractively therebyclearing the register provided the operator has copied the old balancein the same way in both the Old Balance column and the Proof column. Inorder that the operator may be made aware of the fact that the oldbalance has been correctly copied, it is desirable to automaticallyprint a clear sign in the Proof column, and this cannot be accomplishedwith a machine constructed in accordance with my prior Patent No.2,372,681 referred to above.

It is, therefore, a primary ob'ect of this invention to provide, in acombined typewriting and computing machine, an improved arrangementwhereby a star or other clear sign may be automatically printed in anydesired columns of a work sheet without the necessity of taking anautomatic total in such columns.

It is a further object of this invention to pro vide a reliably operablearrangement whereby a clear sign will be printed at only certaindefinite preselected letter space positions.

It is a still further object of this invention to provide an improvedmeans whereby a clear sign will be printed only when the particularregister selected for operation in a certain column is clear.

It is another object of the invention to provide a means for printing aclear sign which is operable early in the second half cycle of acyclically operating computing machine.

These and other objects, features and advantages of the presentinvention will become more readily apparent as the description of apreferred embodiment of the invention proceeds.

Referring now to the-drawings:

Fig. 1 is a perspective view of a portion of a combined typewriting andcomputing machine showing the details of the present invention,

Fig. 2 is a side elevation of the general operator mechanism and shows aportion of the means for rocking the registers into their adding orsubtracting positions,

Fig. 3 is a View similar to Fig 2 but shows the relation of the partsafter a cycle has progressed to approximately the one fourth point,

Fig. 4. is a view similar to Fig. 2 but shows the relation of the partsat the time a cycle has reached the halfway mark,

Fig. 5 is a side elevation of the tens carry-over mechanism and showsthe means for restoring the clear sensing feelers to their normalposition,

Fig. 6 is a perspective view showing part of the mechanism for releasinga state control slide for forward movement to an addition or subtractiondeterminative position,

Fig. 7 is a front elevational view of a portion of the mechanism shownin Fig. 6,

Fig. 8 is a plan view of a modification of one of the features of theinvention,

Fig. 9 is a plan view of a further modification of one of the featuresof the invention, and.

Fig. 10 is a perspective view showing the mechanism whereby variousfunctions of the machine are controlled by the carriage.

Describing first the cycling mechanism and referring primarily to Figs.2, 3 and 4, it will beobe served that the usual general operator bar ithas been provided. During a cycle of operation of the machine, generaloperator bar it is moved from its Fig. 2 position to the position shownin Fig. 4 and then back to the Fig. 2 position by means consisting ingeneral of a bar it to which said general operator bar is operativelycon.- nected. The bar H is moved toward. the front of the machine andback to the Fig. 2 position by means of a crank arm i2 fixed to a shafti3 and provided with a roller l4 fitting within a groove in a plateIS'secured to said bar through the intermediary of a stiffening: memberll. The shaft i3 is connected for one-revolution operation to acontinuously rotating power source through the usual one-revolutionclutch, as described in my prior Patent No. 2,178,702.

The forward end of bar I! is provided with rack teeth i8, which areconstantly meshed with a pinion l9 rotatable upon a fixed stud 2% Fixedto a cross shaft 2!, which corresponds to shaft 7 65 of Patent No.2,178,702, mentioned above, is

a gear segment 22 which is meshed with pinion 19. By referring to myabove mentioned patent, it will be seen that the other end of shaft 2|carries a gear segment similar to segment 22, which, through a pinionsimilar to pinion I9, is drivingly connected to a rack bar similar tobar ii for moving the opposite end of general operator bar Iii, thusassuring'that the two ends of the general operator bar will move inunison.

As seen in Figs. 2, 3 and 4, a generally V -shaped member 23 isfixed tothe cross shaft 2 I, and upon one arm of said V-shaped member is pivotedat as a pawl 25. A spring 26 extends between a pin 21 on a tail portionof said pawl and a pin 28 on the other arm of said V-shaped member andurgessa'id'pawlin a clockwise direction, as viewed in Fig. 2, about itspivot 24. Pawl 25 has an extended end portion 29 providing a pair ofshoulders rtil-and 3! between said end portion and the main body of thepawl for a purpose which will presently appear.

Slidably mounted upon a. square stud32, fixed to the framework, is anarm33', one end: ofwhich' is pivotally connected at 31% to'an arm 35:fixed-.to' across shaft 3%. Crossshaftiitis similar to shaft We of myprior Patent No. 2,192,365; and serves when rocked to move a selectedregister or reg.- isters from a. normally neutral to; an adding, orsubtracting position, as fully explained in. said patent. Shaft 38 isrockedv from its Fig. 2: positionto its Fig. 3 position, by rearwardmovement. of the arm 33, andfor. moving saidarm the fol.- lowingmechanism is provided.

A cam plate. 3.7 having a cam slot 381s pivotally mounted upon a, shaftfixed in the frame of; the machine andis held upon said shaft by means.of. a screw 32. A. pair of. push pins 82, and 4:! are mounted in. the.cam plate. 3.7, the push pin 2H. co.-, operating with shoulder 39, ofthe pawl 25'and the pin 25 cooperating with. shoulder 3! of said pawl. Acam follower. G2 is fixed to the arm 33 and rides in the cam slot 28.

As previously pointed out, the bar II is moved toward the front of themachine, that is to say from the Fig. 2 position to the Fig.l-positionduring the first half of the cycle. As will. read ly beunderstood, the forward movement of. bar I I- will result. incounterclockwise rotation of segmentZZ and V-shaped member 23. Duringapproximately the first quarter of the cycle, the pawl 25- will be heldup in the position shownin Figs.,2 and} so that extension 29 andshoulder 30 thereon will be resiliently held in engagement with push.pin 40 by the spring 28. As the V-shaped member 23 begins itscounterclockwise. movement, the shoulder 30 on pawl 25 will push the pin46- from the Fig. 2 position to the Fig. 3 position thereby rotating thecam plate 3'! counterclockwise about its axis. Since the follower 42 onarm 33'stays in the cam slot 38, counterclockwise rotation of cam plate3'11 from its Fig. 2 position will result in. a rearward movement of arm33 to the Fig. 3 position, as will readily be understood.

As the arm 33 moves rearwardly, the previously selected registers willbe moved into an adding or subtracting position by the resultantrotation of shaft 25, as explained in my prior. Patent No. 2,192,365,referred to above. The registers are, of course, moved to theiroperative positions before the general operator bar Hi has moved farenough to pick up any of the usual differential operator bars. 7

As the cycle progresses from the Fig. 3 position I to the Fig. 4position, the pawl 25'is movedby the pin and into engagement with pushpin 4| and held resiliently engaged therewith by spring 28, as shown inFig. 4.

During the second half of the cycle, the crank arm [2, by continuing itsclockwise rotation, draws the rack bar I I toward the rear of themachine to return the parts from the position shown in Fig. 4 to theirnormal position shown in Fig. 2. This rearward movement of bar II will,of course, result in clockwise rotation of gear segment 22 and V-shapedmember 23. As V-shaped member 23 rotates clockwise, the shoulder 31 onpawl 25 pushes against pin 41 on the cam plate 3! thereby rotating saidcam plate in a clockwise direction and causing the cam follower 42 andconsequently the arm 33 to move toward the front of the machine. Forwardmovement of arm 33 causes counterclockwise rotation of shaft 36 andconsequently rocks whichever register or registers have been moved to anadding or subtracting position during the first part of the cycle backto a neutral position, as explained in my prior Patent No. 2,192,365,referred to above.

For resiliently holding the cam plate 31 in its two operated positions,a detent is provided. Said detent may conveniently consist of a member43 provided with notches 44 and constrained to rotate with said camplate and having in cooperation therewith a pawl 45 pivotally mounted at46 upon a stationary part of the machine and carrying a roller 41 whichis urged by a spring 48 into engagement with member 43.

As explained in my Patent No. 2,192,365, referred to above, a merecycling of the machine will not result in the rocking of a register intoits adding or subtracting position. In order that a register may bemoved into an operative position during a cycle, it is necessary firstto select one or more registers. In the type of machine with which thepresent invention is particularly concerned, register selection ispredetermined and is accomplished by the carriage of the machinedepressing one or more register selecting cam plates. Depression of aregister selecting cam plate causes, among other things, the withdrawalof an add latch 49 (see particularly Fig. 1) from a notch in a statecontrol slide 50, thereby allowing said slide to be moved toward thefront of the machine by a spring 5! until its forward movement isarrested by a second or subtract latch 52.

The state control slide is provided at its front end with a cam slot 53into which slot extends a follower fixed to a slidable bail. Asexplained in my prior Patent No. 2,192,365, forward movement of statecontrol slide 50 to the point where it is arrested by the subtract latch52 serves to position the slidable bail at a location wherein subsequentclockwise rotation of shaft 36 will rock the register, controlled by theselected state control slide, into its adding position.

Since the particular construction of the slidable bail and itsconnection with the register are not within the confines of thisinvention, the same have not been illustrated in the drawing andreference is to be had to my Patent No. 2,192,365 for the detailsthereof.

As likewise explained in my PatentNo. 2,192,- 365, the depression of asecond cam plate by the carriage will withdraw the subtract latch 52 andallow state control slide 50 to move forward to its fullest extent,provided the add latch 49 has first been withdrawn, to thereby positionthe above mentioned slidable bail in a location such 6. that subsequentclockwise rotation of' shaft 36 will rock the register into itssubtraction position.

In my prior Patent No. 2,160,487, an arrangement is described whereby asingle register may be made to perform the function of two registers bythe expedient of operatively connecting only half of the differentialoperator bars at a time for that register to the usual denominationaljacks which are depressed seriatim by the carriage during its travelacross a column. In the machine constructed in accordance with thepresent invention, a good part of the register selecting mechanism hasbeen preserved and while, as described below, the machine in its presentform is not provided with mechanism enabling one register to serve astwo registers, it lends itself to comparatively simple change-over to asplit register machine if such is desired.

Referring now to Figs. 6 and 7, it will be seen that the machine of thepresent invention is provided with a pair of coupler section shifters 54and 55 similar to coupler section shifters III of my above mentionedPatent No. 2,160,487. Each of the coupler section shifters is guided forvertical sliding movement by a plurality of guide studs 56 fixed in astationary register bar guiding plate 51'. When the coupler sectionshifters are raised from the Fig. 6 position to the Fig. 7 position, thecouplers 53, only partially shown in Fig. 7, are raised to a position tooperatively connect the differential operator bars with the abovementioned denominational jacks, as will readily be understood.

The coupler section shifters 54 and 55 are operated by the depression bythe carriage of a cam plate 355. As may readily be seen in Fig. 10,there is a cam plate 335 corresponding to each of the registers of themachine; in the present instance three have been shown. The rearmost camplate 330 rests upon a tab 33! of an intermediate plate 302. Through apush rod 353, the plate 352 is operatively connected to one end of alever 55 pivotally mounted upon a shaft 55. It is to be understood thatthere is an intermediate plate 332, a push rod 353 and a lever 59corresponding to each of the other register selecting cam plates 3%, butthat for clearness of illustration, they have not been shown.

Operation of lever 53 causes rotation of a lever 50, Fig. 6, pivotallymounted upon a part of the framework 6| of the machine by a stud shaft62. There is a pin-and-slot connection 53 between one end of lever 53and an arm 35 fixed to one end of a rock shaft 65 mounted in a pair ofears 5%; oi the framework 5!, so that rotation of lever es causes shaft54 to be rocked clockwise, as viewed in Figs. 6 and 7. An arm 3? isfixed to the opposite end of rock shaft 55 and carries a stud 53 whichextends into an opening 59 in the coupler section shifter It will,therefore, be understood that when the end of lever 53 is raised fromthe position shown in Fig. 6, such movement will result in raising thecoupler section shifter 5 Since it is not desired to use the registercontrolled by a single state control means 55 as two registers, it isnecessary to raise the coupler section shifter 55 at the same time thatshifter 54 is raised, and for that purpose, the following mechanism isprovided.

An intermediate lever it, having one end ii overlying the stud 83, ispivotally mounted upon the guide plate 57 by means of a stud i2. Theopposite end of lever 15 overlies one end of a lever i3, which lever isalso pivotally mounted upon the guide plate 5'! by a stud 14. The leveri3 is simi- 7 lar to latch rod retracting lever. 268 of my Patent No.2,160,487, but unlike said lever 256, the lever 13 is provided with astud 15 extending into an opening it in the coupler section shifter55 sothat when the shifter-54 is raised bythe stud 5,8,

the levers l9 and 13 are rocked in such manner as to cause the stud 15on lever 13 to raise the shifter 55, as will readily be understood.Lever 13 is normally held in its inactive position by a spring '23.

As in the construction .explainedin my Patent No. 2,160,487, the addlatch 49 is provided with a notch ll fitted against the edges of lever13. Thus it will be understood that the depression of a particular camplate 300 by the carriage of the machine will serve to .completelycondition a given register for-addition, inasmuch as the depression ofthe cam plate will allow the state control slide to move forwardto itsadd position and will also operatively connect all of the differentialactuators for said register with the universal set of denominationaljacks. The upper ends of the denominational jacks are indicatedgenerally at 35 in Fig.10.

In the machine in which the present invention has been embodied, thesubtract latches 52- are all withdrawn from engagement with theirrespective state control slides 50 at the same'time. Each subtract latch52 is pivotally connected as at '53, Fig. 6, to an arm 79 fixed to auniversal cross shaft to. When the cross shaft 80 is rockedcounterclockwise from its 'Fig. 6 position, all of the subtract latches52 are raised.

For a description of a preferred means of operating the shaft to,reference is to be had to Fig. 10. A subtraction determining cam plate305 is operatively connected through an intermediate plate 363 and apush rod'3fll to one end of an L-shaped lever 308. The L-shaped lever388 is mounted upon a rock shaft 309 and is connected by a bail 3 i iito one end of a lever 3 H also mounted upon the shaft 3&9. The lever 3|l is urged in a clockwise direction, as viewed in Fig. 10, by a spring 3i 2 and is pivotally connected by a pin 3 I 3 to one end of a link 3 lt. The opposite end of link 3 i t is pivotally connected to one end of alever 3 I mounted upon a'rock shaft 3H6. The opposite end of lever 35 5is connected by a bail 3H to one end of a latch member 318 also mountedupon the shaft 3 I B.

The spring 3i2 serves to hold the cam plate 335 in an elevated positionand :also serves'to position a tongue 31% or" the latch member 358underneath one arm of a generally T-shaped member 326. The member 320 ispivotally connected at 152i to a stationary part of the machine and isurged by a spring 322 in aclockwise direction, as viewed in Fig. 10. Onearm of the mem- 32ii is pivotally connected by a pin 32] to a link 322.The link 322' is provided with a slot 323 into which is fitted a pin 324mounted upon an arm 325 fixed to the aforementioned shaft 80. A spring32% connects the pin 324 to an ofiset portion 327 of the link 322.

If a register is to be selected for subtraction in a particular column,a column unit 144 which will control the operation of the machine inthat column is provided with a tappet 328 fordepressing one of the camssee to select the register for addition and to raise the couplers 58, aspreviously described, and is also provided with a tappet 329 fordepressing the subtraction cam plate 3335. Through the linkage systemabove described, depression of cam plate 305 serves to withdraw thetongue 319 from beneath the arm of Tshapedmember 320, whereupon thespring 322 rocks the member 320 clockwise until said member abuts astationary pin 330. When the member 320 is in abutment with the pin 330,the arm of said member lies in front of the tongue 3E9 so that eventhough the tappet 329 should leave'the cam plate 395, said plate willnot at that'time move upward because the tongue 3l9 cannot move to theright as viewed in Fig. 10.

When the member are is rocked clockwise, the link 322' pulls the pin 324on arm 325 toward the rear of the machine to thereby rock the crossshaft in a counterclockwise direction as viewed in Fig. 10 and therebywithdraw all of the subtract latches 52, as previously explained.

If a register is to be selectable in a. given column alternately forordinary computing and for automatic total-taking, the column unit willbe provided with two tappets 32B and two tappets 329. One of the tappets328'and 329 will cooperate withthe cam plates 3% and 395 when saidcamplates are in theirforward, or ordinary computing, positions and oneof the tappets .323 and 329 will cooperate with the cam plates 3Mand 355when saidcamplates are in their rearward, or automatic total taking,positions. It is well known that in-machines of the type with whichthisinvention is particularly concerned, the cam plates which controlthe functioning of the machine may be rocked from a non-total-takinposition toa total-taking position, and one mannor of rocking suchplates is explained in my prior Patent No. 2,372,681.

Onearm of the T-shaped member 320 is provided witha camportion 33! and adwell 332 for cooperating witha pin 333 .carriedby a bar 334. The bar33iis part of the means for moving the general operator bar It and earlyinthe .cycle the pin 333 contacts the cam portion 331 to thereby rockthe'member 323 in a counterclockwisedirection. As the membersze movescounterclockwise, the offset portion 327 of link 322', through thespring326, pulls upon :thetarm 325 to attempt to rock the cross shaft '89 in.a clockwise direction. If a register has been selected for subtractionthe shaft 8d cannotat'this time move clockwise because thetend of .thefsubtract'flatch will be resting upon the state control slide. Spring826 will, therefore, yield until later inithe cycle when the statecontrol slide has been returned to its normal position, in a manner tobe later described, whereupon the springtzfi will snap the subtractlatches down into theirrespectivenotches in thestate control slides.

Thecolumn units l lare adjustably mounted uponvthe carriage, partiallyindicated at 335, and may be placed in any desired positions inaccordance with the work-sheet columns.

Referring now to Figs. 1 and 5, a portion of the base of a combinedtypewriting and computing machine, of the type to which the presentinvention is particularly adapted, is shown. Since the present machinehas three single registers, or'three interspersed registers, asdisclosed in'my recently issued'Patent'No. 2,436,055, three fore-and-aftmovable state control slides 50 are at least partially shown. Since theoperation'of all of the registers and all of'the state control slides isidentical, only one state'control slide has been shown in its entirety.

Extending parallel to the state control slide 59 for'each register is afore-and-aft movable slide 8|. Each slide BI is provided-with anelongated s1ot-82 at its forward end and is mounted I01 guided'movementupona-pin 83 fixed to the framework of the machine. Each slide has anelongated slot 84 in its rear end guidably slidable upon a headed stud85 fixed in a state control restorer bar 86, the operation of which willbe presently described. Each slide 8| is constantly urged toward therear of the machine by a spring 81. In its forward end, each of theslides 8| is provided with a slot 33 for receiving one arm of a bellcrank 89 stationarily pivoted at 90 to the machine framework. To theother arm of each bell crank 80 is articulated, by a pin-andslotconnection SI, a sensing bar generally indicated at 92. One leg 93 ofsensing bar 92 extends through an opening is (see Fig. 5) in theframework of the machine, and another leg 95 thereof is guided in agroove 96 cut into the machine framework. At its upper end, each sensingbar is provided with a guide member 91 riding within a slot 98 in astationary member 99 and with a sensing spur I for a purpose to bepresently described. Each of the sensing bars 02 is urged to itsinactive position by a relatively light spring 92, as shown in Fig. 5.

A register clearance detecting bail bar IOI has side arms I02, which arepivotally mounted upon side plates I03 of a register frame. Only one ofthe side plates I03 is shown in Fig. 5, and inasmuch as the plates I03correspond to plates IOI of my Patent No. 2,436,055 and the registers tobe used in the present machine may be identical with the registersdescribed in detail in said patent, reference is to be had thereto forthe details thereof. The particular machine chosen for illustration isof the interspersed register type, as disclosed in my said patent andfor that reason, the bar IOI is illustrated in Fig. 1 as having a row ofcam-bevel-sided teeth I05 and interdental notches I05. As described insaid patent, a register consists of a plurality of wheels I06 for eachdenominational order, and a detent arm I0? is provided for each wheel.Each wheel is provided with a pair of crescents I00 out into adjacentteeth. When the wheel is in the rotative position corresponding to 0,the crescents I08 are aligned with a tail portion of detent arm IN. Aspring I09 urges each arm I Ill toward its wheel. It will, therefore, beapparent that when the crescents are aligned with the tail, portion ofsaid arm, the arm will not stand out as far as when the wheel is in aposition other than 0 and the crescents are not so aligned. The purposeof the interdental notches is to allow the detent arms I01,corresponding to the Wheels of a non-selected register of theinterspersed group, to be positioned outwardly by wheels of that groupwhich are not in a 0 position without affecting the bail bar I 0| all asdescribed in my Patent No. 2,456,055, referred. to above.

Bail bar MI is urged by a spring IIO toward the arms I03 and when aregister is clear, that is to say when all the wheels of the registerare standing at 0, bar IOI is so positioned as to be out of the path ofdownward movement of spur I00 of feeler member 92, as may be seen inFig. 5. When any one or more wheels of a register are standing at aposition other than 0, arms I0! corresponding to such wheels are movedoutwardly thereby moving the bail bar IOI outwardly and into the pathof, and preventing downward movement of, spur I00, as shown in Fig. 1.

Thus it will be seen that the spring-urged foreand-aft movable slide SI,together with the sensing bar 92 and its sensing spur I00, constitutes10 a sensing means for ascertaining whether a register is clear orwhether there is an amount standing in the wheels of said register.

While above, reference is made to a selected register for purposes ofexplaining the presence of the interdental notches I05 in the bail barIOI, for the remainder of the specification it is to be understood thatwhen reference is made to a selected register, the term is intended toinclude a single register of a multiple single-register machine, as wellas one register of an interspersed group.

Each of the slides 8I is provided with a notch MI in the side thereof,and extending into each notch I I i is an arm I I 2 fixed to a crossshaft 5 I3. Also fixed to said cross shaft is an arm I I4 pivotallyconnected at I I 5 to a vertically movable member I I6 guided in astationary cross piece III', as seen in Fig. 5.

The upper end of member II 6 abuts a flange II8 on one end of a lever H9pivotally mounted upon a stationary shaft I20. The lever H9 is urged bya spring I2! in a clockwise direction, as viewed in Fig. 1, about theshaft IN, and at the end opposite the flange H8 is provided with aflange I 22 overlying one end of a draw link I23. The draw link 5223 isurged to inoperative position by a spring I24 and is provided at one endwith a toothed pawl I 25 for engagement with the usual snatch roll I26.Intermediate its length, the draw link I23 is pivotally connected to oneend of a stationarily fulcrumed lever I27 to the opposite end of whichis operatively connected by a link I28, a type bar I29 carrying a staror other clear sign I30.

When any one of the slides 0| is moved by its spring 8'! toward the rearof the machine, the forward edge of the notch III will pull the arm H2toward the rear thereby rocking cross shaft H3 and causing thevertically movable member M0 to be raised. This raising of member I I5will, of course, rock the lever H5 and thereby cause the pawl I25 ondraw link 5223 to be moved into enga ement with the snatch roll I26. As

' the draw link I 23 is moved by the snatch roll, the

type bar I 20 will be moved into engagement with the work sheet carriedby the platen of the typewriter unit, as is well known.

While that part of the star printing train from the lever M9 to the typebar I29 is shown in Fig. 1 as being located to the left of thevertically movable member I I6, it has been so shown only for the sakeof clearness of illustration, and in the actual construction of themachine, it is located to the right of member I6.

When work is being performed, which in a machine with which thisinvention is primarily concerned may be either a manual item entry or anautomatic total in a column on a work sheet, it is essential that a staror other clear sign be printed only if the particular register in whichthe work is being performed in that column becomes clear. In otherwords, unless the particular register selected to be moved to its addingor subtracting position from its normally neutral position is clearedduring the cycle which follows the printing operation, a star should notbe printed.

To insure that clear sign printing is controlled by the particularregister selected for operation in a given column, an interlock has beenprovided between the state control means for each register and the clearcondition sensing means for that register which will prevent theoperation of the sensing means at all times when the state control slidehas not moved forward.

. In Fig. l is shown a member I3I pivotally mounted upon the pin 83,which, as previously pointed out, also serves to guide the forward endof slide. 8i. A pin-and-slot connection I32 serves to operatively.connect each of the members I3I to its state control slide, and eachmember I3! is provided. with a hook I33 extending into the pathof'movement of a pin I34 mounted in each of the sensing slides BI. Untila state control slide 56 has been moved forward to'determine an addingor subtracting condition of its register, the. hook I33 will preventrearward movement of the associated sensing slide 8| and, therefore,prevent operation of the clear sign printing train. When a state controlslide 58 moves forward, the member IBI associated therewith will becaused to swivel about the pin 83 due to the pin-andslot connection I32,and this swiveling of member I3I Will cause the hook I33 thereon to moveout of the path of movement of the pin I35, as will readily beappreciated.

In some instances, it is desirable to prevent the printing of a clearsign at all times except when a. register has been selected forsubtraction, and for accomplishing that'result, the arrangement shown inFig. 8 is contemplated. Attached by a screw I35, or otherwise, to themember i3! is a member I36 having an upturned lip 13? for bearingagainst one edge of the member I3I and having an elongated tail I38 forextending beyond the end of book I33.

If the add latch 45 is withdrawn and the state control slide 55consequently moved forward, in the direction of its arrow in Fig. 8, tothe position wherein its register will be rocked to its adding positionduring the cycle, as previously explained, the hook I33 of member ISIwill be withdrawn from the path of movement of pin I es, but theelongated tail I38 of member I3 3 will not be moved far enough to be outof the path of pin I34. Consequently, the sensing means cannot operatewhen a register has been selected for addition. If, however, thesubtract latch 52 is now withdrawn to allowthe slide 58 to continue itsforward movement, such additional forward movement will cause the memberI35 and member I36 attached thereto {to be rotated about the pivot point83 to a position wherein the elongated tail portion I38 is out or" thepath of movement of pin I34, and'the sensing slide 85 will consequentlybe able to move toward the rear of the machine, indicated in Fig. 8 bythe arrow on member 8|.

Should it be desirable to prevent printing of a clear sign at all timesexcept when a register is selected for addition, it is contemplated toemploy the arrangement shown in Fig. 9, wherein the member I36 of Fig. 8is replaced'by a member 315. The member I39 is fastened to the memberI3! by a screw IdIl, or otherwise, and is provided with a lip MI,similar to the lip I31 "of'member I36, for bearing against the side ofthe member I3I. Member I39 is provided with a tail portion M2, which islonger and wider than the tail portion I38 of member I36 and is cut awayat It to provide a space between the hook I 33 and the end of tailportion I42 into which the pin I3 on slide BI may move. If with theconstruction shown in Fig. 9, the add latch 59 is withdrawn to allow thestate control slide 59 to move in the direction of its arrow in Fig. 9

' to the position wherein the register is selected for addition, themember I3I and the m mb I39 connected thereto will be rotated about thepivot 83 to a position wherein the hook I33 is outof the path ofmovement of' the pin It'd, but the end of tail portion I42 will not havemoved to a point of alignment with said pin. The sensing slide SI will,therefore, be free to move to' the rear, the direction shown by itsarrow in Fig. 9, and consequently institute the-printing of a clearsign, as previously explained.

In the Fig. 9 construction, if both the add and subtract latches arewithdrawn from the state control slide, said slide will move all the wayforward and thereby rotatemembers IS'I and I39 to a point where the endof tail portion I62 will block rearward movement of slide Eli. It willlater become apparent that there is no possibility of the slide SImoving to the rear during the time required for the state control slideso to move to its subtract position. That is to say, whenever a registeris selected for subtraction, the opening formed between the hook I33 andthe end of tail portion I52 by the cutaway I43 is momentarily exposed tothe pin I3 3, but the slide 8! is prevented from movement at that timeby other means.

When a clear sign is to be printed in a column on a work sheet, it isdesirable that said sign be printed at only one particular letter spaceposition of the carriage and said letter space may appropriately be theone immediately following the lowest denomination of the column ofnumbers.

Column unit hid, in addition to the tappets 328 and S29 previouslyreferred to, is provided with a tappet 335 for depressing seriatim theaforementioned denominational jacks see; As described in my prior PatentNo. 2,323,622, as the carriage escapes from the position wherein thetappet 338 is resting upon the jaoksil i corresponding to the lowestdenominational order, a cycle instituting tooth 33? on the column unitI44 passes over a cycle trip lever partially indicated at 338 in Fig.10. Depression of the cycle trip lever 338 causes the machine to cycle,as explained in my said'Patent No. 2,328,622.

After the tooth 33? passes over the cycle trip lever 338, the carriagecomes to rest in the letter space position immediately following thelowest order letter space position, and it is in this letter spaceposition that it is desirable to print the clear sign. For enabling theslides 3| to move rearward to. thereby institute clear sign printing,the column unit I 34 is provided with a tappet, or dog, I 35 forcooperating with a tooth I46 one plate I47. The dog IE5 is so shaped andpositioned as to rest upon the tooth I46 only when the carriage is inthe letter space position immediately following the lowest denomination.

Referring now particularly to Fig. 1, it will be seen that the tooth Iis a part of a member I48 carrying a headed stud I69 mounted within aslot I59 in the plate i4? and a headed stud I5I mounted within a slotI52.

Member I48 is urged upward toi'the position shown. in Fig. 1 by a springI53 extending between the headed stud I5I and a hole I55 in the plateI41. The plate I ll and its tooth carrying member I48 are constructed asmore particularly explained in my prior Patent No. 2,372,681, and byreferring to said patent, it will readily be understood that when thetooth I46 is depressed by a pressure applied from the right, the plateI41 will be depressed, but when the tooth is struck from the left, themember I48 is merely depressed 13 with the headed studs I49 and IIriding down in their respective slots without depressing the plate I41.The purpose of using such a plate is so that the plate I41 will not bedepressed during carriage return operations.

When the plate I41 is depressed, it in turn depresses a plate I55, whichthrough a push rod I55 rocks a crank arm I51 fixed to a shaft I58.

The shaft I58 carries three rods I59 which are normally held inalignment with the sensing slides BI, as shown in Fig. 1, by a helicalspring I60 acting upon the shaft I58. Therefore, it will be obvious thatthe sensing means comprising the slides 8i can operate at only onecolumnar letter space position, since at only one letter space positionin a column is the shaft I58 rotated by the depression of plate I41 toremove the rods I59 from alignment with said slides.

A dog I45 for depressing plate I41 may, of course, be placed upon anycolumn units which control columns in which it is desired to print aclear sign.

If desired, the plate I51 may be made to rock to the rear whenever atotal is taken in a manner similar to that described in respect to plate455 of my hereinbefore mentioned Patent No. 2,372,681, so that a clearsign may be printed in any column whenever a total is automaticallytaken in said column but not printed when an item is merely entered insaid column. If the plate I41 is made rockable during automatic tota1taking operations, a dog I45 is provided upon each column unit I44 in aposition to be in operative alignment with the tooth I46 when plate It?is in its total position. In any column, for example a proof column,wherein it is desired to print a clear sign at times when a total is notautomatically taken, the dog I45 will, of course, be so positioned as tobe in operative alignment with the tooth I45 when plate I41 is in itsunrocked or non-total-taking position.

In addition to the clear sign printing being confined to one particularcolumnar letter space position and being dependent for its operationupon register selection, it is necessary that said printing be delayeduntil after the cycle has progressed to a point where the registerwheels have been completely turned. Not until after the differentialoperator bars have completed their forward movement and the tens carryover has had time to operate is it possible to ascertain whether thecomputation has resulted in a clear register. For the purpose ofdelaying operation of the clear sign printing train until the secondhalf of the cycle, the following mechanism is employed.

A crossbar l6i, the operation of which will later be more fullyexplained, is normally positioned as shown in Figs. 1, 2 and 5. Each ofthe sensing slides BI is provided with a post I52, which is in abuttingrelation to the crossbar ISI when the machine is in its normalcondition, that is, when a cycle is not in progress. When a cycle hasprogressed to approximately the one quarter point, the crossbar ISIbegins to move toward the rear of the machine so that by the time thecycle has progressed to the halfway mark, the crossbar I5I has moved tothe position shown in Fig. 4, wherein it no longer interferes with freerearward movement of the slides 8|.

Fixed to the cross shaft 36, which, as previously explained, is rockedclockwise, as viewed in Figs. 1 to 4, at the beginning of a cycle, is anarm I53 to which is pivotally connected at I54 a link I65 having a slotI56 in one end thereof. To the cross shaft H3, which, as previouslyexplained,

must be rocked counterclockwise, as viewed in Figs. 1 to 4, to instituteoperation of the clear sign printing train, is fixed an L-shaped arm it!provided with a pin I68 extendin into the slot I66. Arm I61 is alsoprovided with a pin I69 between which and a stop pin I10 on theframework of the machine extends a light tension spring I1I forresiliently holding said arm against said stoppin and consequentlyholding the cross shaft II 3 in its neutral position.

The general operator mechanism is so timed as to cause the cross shaft36 to complete its clockwise rocking movement before the crossbar I6Ibegins its rearward movement. Therefore, the link I55 is moved forwardto the position shown in Fig. 3 wherein the pin 58 on arm It? ispositioned in the back of slot I55 before the crossbar I5I has startedto move away from posts I62. Thus while the crossbar IiiI serves to lockthe clear condition sensing slides 8i before the cycle begins, it willbe apparent that this function is taken over by the link I55 and itspinand-slot connection with the L-shaped arm I51 as the cycle gets underway.

Eearly in the second half cycle, the cross shaft 36 is rockedcounterclockwise of its Fig. 4 position to return the selected registerto its normal position, and shaft I I3 would at that time be free to berocked were it not for the following arrangement.

Fixed to the cross shaft II3 near the end op posite the L-shaped arm I51is an arm I12 carrying a roller I13 on the free end thereof. Secured tothe general operator bar It! by means of a screw I14, or otherwise, is amember 15. As the general operator bar II) advances to the half cycleposition, the member I15 moves over the roller I13 on arm I12, as shownin Fig. 4, to thereby prevent the cross shaft I I3 from being rocked. Aswill readily be appreciated, the member I15 will remain in engagementwith the roller I13 until the second, half of the cycle has progressedfar enough for the register to be returned to its neutral positionwherein the bail bar IBI will be in a position to block downwardmovement of the sensing bar 92 if the register is not clear, aspreviously explained.

Thus it will be seen that means has been provided for delaying operationof the clear sign printing train until the second half of a cycle hasgotten under way. By varying the length of the member I15 or the armI12, clear sign printing may be instituted at any time during the secondhalf cycle that is found desirable.

After a register has been selected. for addition or subtraction byforward movement of its state control slide 58, it is necessary toreturn the state control slide to its neutral position during the cyclefollowing the computation, and, for this purpose, the hereinbeforementioned bar is employed. Attached to the bar 86 is an arm I pivotallyconnected at I11 to an arm i'ia fixed to a shaft I19. Also fixed to theshaft I19 is an arm I80 pivotally connected at l8I to a hook link I82.Hook link I62 is cooperative with the general operator bar II) in amanner fully described in my copending application No. 2,654, filed J anuary 16, 1948, it being sufficient here to mention that the hook linkI32 is provided with a step I83. As the general operator bar it) movesforward, the hook link 182 is lifted so that during the return stroke ofsaid general operator bar, step I83 is caught by said bar, and the hooklink I82 is thereby drawn toward the rear of the machine. Rearwardmovement of the hook link I82, will, of course, result in rearwardmovement of the bar 85, aswill readily be appreciated; Each of the'statecontrol slides 58 isprovided with a pin Its extending. into the path ofmovement of the bar 83, so that as said; bar moves toward the rear ofthe machine, any slide 53 which has been allowed to move forward will bepicked up by the bar 85 striking the pin ISIS thereon and returned toits normal position. At the very end of the cycle, the step I83 iskicked down out of engagement with the general operator bar It, and aspring I85 attached to the bar 86 returns said bar and the hook link I32to the position shown in Fig. 1, as described in my copendingapplication-No. 2,654, referred to above.

After any sensing slide 8| has moved rearward toinstitute action ofthe-clear sign printing train during acycle, as previously described, itis necessary thatsaid slide be returned to its normal position in orderthat it may be ready to perform its sensing. function during the nextcomputing operation. Since the particular means employed hereinfor' thatpurpose-is a part of the usual tens-transfer and fugitive-one mechanism,said tens-transfer and fugitive-one mechanism will be briefly described,but for a full description of the-operation thereof reference is to behad to my prior Patent No. 2,192,365.

Referring now to Fig. 5, one of the differential operator bars isindicated at I85. Said bar car ries a plurality of index pins I8? andhas rack teeth I83 located upon the forward end thereof. By referring tomy Patent No. 2,192,365, mentioned above, it will readily be apparentthat there is a differential operator bar I239 for each denominationalorder of a register. The rack teeth on each of the bars I86 are inconstant mesh with the teeth of an idler pinion I89.

The register wheels I06 are rocked rearward into engagement with theidler pinions I89 for subtractive operation and are rocked downward intodirect'engagement with the rack teeth I88 for additive operation.

A lever I98 corresponding to each of the differential operator bars I96is pivotally mounted upon a bracket IQI fixed to the general operatorbar Iii. As is well known, the index pins I8? are set in accordance withthe operation of the numeral types of the typewriter unit, the pin beingset, as shown, when none of the other pins has been set. As the generaloperator bar II! is moved forward during a cycle, the differentialoperator bars I85 are picked up by the contact of lever I96 andwhichever of the index pins I8? has been set, and moved forward torotate the register wheels I65 by an amount corresponding to the setindex pin. On its return stroke, the general operator bar It picks up anabutment I92 on each of the differential operator bars to return same totheir normal position. The bars I88 are actually moved the lastincrement of movement to their home position by a spring I93 engagingwith a notch in said bars.

If a register wheel is rotated through the transfer point, that is, from9 to 0 or from 0 to 9, a carry-over trip lever I94 is moved outwardly ofthe position shown in Fig. to rock a bell crank I95 one end of which isin engagement with a carry-over bar I96. Each carryover bar I93 ispivotally connected to a stationarily pivoted lever I9? carrying aroller I93 on one end thereof. The roller I98 on the lever I9! is inlateral alignment with the lever I90 of the next highest denominationfor a purpose present ly to become apparent.

A spring I99 urges the carry-over bar. I96 forward and downward, forwardmovementbeing normally prevented by contact of the lever I91 with astationary shaft 209 and downward movement being arrested by contactbetween the forward end of'bar I 96 and a guide comb ZIII.

Before the'carry-over bars I96 can be effectively operated, it isnecessary that they be drawn a short distance toward the rear of themachine so that the levers I9'I are no longer. in contact with thestationary shaft 260, and for this purpose, a crossbar 202 is providedfor cooperative engagement with a shoulder. 293 on said carry-over bars.The crossbar 262 is connected to move withthe crossbar IBI, previouslydescribed, by means'of brackets 204, only one of which is shown.

Crossbar IGI is connected at its opposite'ends between a pair of slides205, only one of which is shown. The slides 205 are each provided with apair of cam followers 205 for cooperating with a cam 2m fixed to thecross shaft 2 I, previously referred to.

During the first half of the cycle, the cam 20! is rotatedcounterclockwise, as viewed in Fig. 5, to draw the crossbar IBI andconsequently the crossbar 2%)? toward the rear. As the crossbar 202moves rearward, it contacts the shoulders 293 of carry-over bars I95 andthereby moves said carryover bars rearward to position a flange 208 onone end thereof in abutment with the set 0 index pin I87 of the nexthighest denomination operator bar I39. If the 0 pin is not set, theflange 2% is positioned in what would be abutting relation with the 0pin if same were set. If, at this time, a register wheel passes throughthe transfer point, the bell crank I95 corresponding to said wheel willbe rocked to lift the shoulder 263 on the corresponding carry-over barout of contact with the crossbar 202. Spring I99 will then be effectiveto draw the carry-over bar I95 forward until the lever I97 contacts thestationary shaft 269. At that time the roller I98 on lever ISI willbe'positioned far enough toward the rear of the machine to intercept theforward movement of the lower end of lever I and thereby cause saidlever to pivot about its connection with the bracket I9 I. The pivotalmovement of lever I99 will be just sufficient to cause the upper endthereof to move the differential operator bar I85 forward by an amountequal to one digital distance and position the set index pin in contactwith the flange 29B of carryover bar I 96. The additional forwardmovement of the difierential operator bar will cause the register wheelassociated therewith to be turned by an amount equal to one digit, aswill readily be understood.

A lever 209, shown in Fig. 5, operates the carryover bar I for thelowest denominational wheel and is connected by a bail 2 II? to the bellcrank I95 which is operated by the highest denominational wheel, thusproviding a fugitive-one mechanism, as will beunderstood and as morefully explained in my copending application, Serial No. 2,654, filedJanuary 16, 1948.

During the second half of the cycle, the cross shaft fl is rotatedclockwise, as viewed in Fig. 5, as previously explained. The resultantclockwise rotation of cams 201, by cooperation with the cam followers2%, will cause the slides 205 and the crossbar 202 associated therewithto move forward until the crossbar 202 clears the shoulders 203 oncarry-over bars I96, whereupon the 17 springs -l 99 will pull saidcarry-overbar down to the position shown in Fig. 5.

As the crossbarl6l' moves forward, it carries forward to its normalposition any sensing slide 8|, which has moved rearward,by cooperationwith the post [62 thereon. Thus it will be seen that the usual'tens-carry-over restorer bar 'IBI is-utilized as a primary lock toprevent operation of the clear condition sensing means and has alsobeen'made to serve as a-restoring means for said sensing means.

From the foregoing description, it will be apparent that anarrangementhas been provided,

in a combined typewriting and accounting machine, whereby a star orother clear sign may be printed in-any desiredcolumn'of a work sheetwhenan operation in that column has resulted in clearing the registerwhichhas been selected foroperation at thatcolumnarposition. It is to beparticularly noted that in accordance with the present invention, it isof no consequence whether the register iscleared as a result of anautomatic total taking operation or as a result ofan item entry. Itis-also to benoted that with an arrangement such'as herein disclosed,the 9 star or other clear sign will only be printed at definitepreselected columnar letter space positions.

'It isalso to be noted that clear sign printing and register selectionare both under control of p the carriage. It is, therefore, possible tocheck back over a work sheet and determine the place where any errormayehave occurred. For example, if a clear-sign does not appear in acolumn wherein an automatic total was taken, it will 7 be evident thatan-error occurred at the time of the automatic total taking operationand the particular register wherein the error occurred may beidentified, since at that'columnar position it will be-known that acertain register was in operation.

Having thus described'my invention, I claim:

1. In a computing machine adapted for printing amounts in a column on awork sheet and having a letter spacing carriage,-a unit on said carriagefor controlling various functions of the machine, a register comprisinga plurality of axially aligned'wheels, and a cycling general oper atorfor runningindexed amounts into the wheels of the register; theimprovement comprising spring-operated sensing means for'ascertainingthe" clear condition of the register, a pair of normally effective lockseach of which is capable of preventing operation of "said sensing means,means'fonreleasingoneof said looks at a predetermined columnarletter'space position of the carriage, means for releasing the other ofsaid locks during a machine cycle, and a clear sign printingtrainoperable only when both of said locks are released and when thesensing means finds the register to be clear.

2. In a computing machine adapted for printing v amounts in a column ona work sheet and having a letter spacing carriage, a unit on saidcarriage for controlling various functions of the machine, a registercomprising a pluralityof axially aligned wheels,.and.a cycling generaloperatorfor running indexedamounts into' the wheels of the register; theimprovement comprising spring-operated sensing means for ascertainingthe clear conditionof the register, a pair of normally efiective-lockseach of which is capable of-preventing operation of'said sensing means,means' for releasing one-of said locks at a predetermined columnarletter space position of the carriage, means for releasing the otherof'said locks during a machine cycle, and a poweractuated clear signprinting train the action of which is instituted by said sensingmeans'when both'of said locks are released and when the sensingmeans-finds the register to be clear.

3.- In a credit balance computing machine having a register Whichismovable to different positions-from a normally neutral position foradding and subtracting, a cycling generaloperator-ior running indexedamounts into the wheels of the register, a state control means fordetermining whether the register is to be moved during a cycle from itsneutral position into its adding or subtracting position, a spring-urgedmember associated with said state control means, an interlock betweensaid state control means and said springurged-rnember constructed andarranged to prevent operation of said spring-urged member at all timeswhen said state control means has not been moved to determine an addingor subtracting condition of the register, and a sign printing train theoperation of which is instituted by said spring-urged member.

4. In a credit balance computing machine having a register which ismovable to different positions from a normally neutral position foradding and subtracting, a cycling general operator'for running indexedamounts into the wheels of the register, a state control means fordetermining whether the register is to be moved duringa cycle from itsneutral position into its adding or subtracting position, sensing meansassociated with the register for ascertaining a clear condition thereof,an interlock between said state control means and said sensing meansconstructed and arranged to prevent operation of said sensing means atall times when said state control means has not been moved to determinean adding or subtracting condition of the register, and a clear signprinting train the operation of which is instituted by said sensingmeans'when said sensing means is operated and upon operation finds theregister to be clear.

5. In a credit balance computing machine having a register which ismovable to different positions from a normally neutral position foradding and subtracting, a cycling general operator for running indexedamounts into the wheels of'the register, a state control means fordetermining whether the register is to be moved during a cycle from itsneutral position into its adding or subtracting position, sensing meansassociated with the register for ascertainin a clear condition thereof,an interlock between said state control means-and said sensingmeans-constructed and arranged to preventoperation'of said sensing meansat all times when said state control means hasnot been moved todetermine a subtracting condition of the'register, and a clear signprinting train the operation of which is instituted by said sensingmeans when said sensing means is allowed to operate and upon operationfinds the register to be clear.

6. In a credit balance computing machine having a register which ismovable to different positions from a normally'neutral position foradding and subtracting, a cycling general operator for running indexedamounts into the Wheels of the register, a state control means fordetermining whether the register is to be moved during a cycle from itsneutral position into its adding or subtracting position, sensing meansassociated with the register for ascertaining a clear condition thereof,an interlock between said state control means and said sensing meansconstructed and arranged to prevent operation of said sensing means atall times when said state control means has not been moved to determinean adding condition of the register, and a clear sign printing train theoperation of which is instituted by said sensing means when said sensingmeans is allowed to operate and upon operation finds the register to beclear.

'7. In a credit balance computing machine having a register which ismovable to difierent positions from a normally neutral position for add-"ing and subtracting, a cycling general operator for running indexedamounts into the Wheels of the register, a fore-and-aft movable slidefor determining whether the register is to be moved during a cycle fromits neutral position into its tracting condition of the register, and aclear sign printing train the operation of which is instituted by saidsensing means when said sensing means is allowed to operate and uponoperation finds the register to be clear.

8. In a credit balance computing machine having a register which ismovable to different positions from a normally neutral position foradding and subtracting, a cycling general operator for running indexedamounts into the wheels of the register, a state control means fordetermining Whether the register is to be moved during a cycle from itsneutral position into its adding or subtracting position, a spring-urgedmember associated with said state control means, an interl cl: betweensaid state control means and said spring-urged member constructed andarranged to prevent operation of said spring-urged member at all timeswhen said state control means has not been moved to determine an addingor subtracting condition of the register, a sign printing train theoperation of which is instituted by said spring-urged member, and meansassociated with said cycling general operator for delaying the operationof said spring-urged member until the last half of the cycle.

9. In a credit balance computing machine having a register which ismovable to different positions from a normally neutral position foradding and subtracting, a cycling general operator for running indexedamounts into the Wheels of the register, a state control means fordeter- 'mining whether the register is to be moved during a cycle fromits neutral position into its adding or subtracting position, sensingmeans associated with the register for ascertaining a clear conditionthereof, an interlock between said state control means and said sensingmeans constructed and arranged to prevent operation of said sensingmeans at all times when said state control means has not been moved todetermine an adding or subtracting condition of the register, a clearsign printing train the operation of which is instituted by said sensingmeans when said sensing means is allowed to operate and upon operationfinds the register to be clear, and means associated with said cyclinggeneral oper- 20 ator for delaying the operation of said sensing meansuntil the last half of the cycle.

10. In a credit balance computing machine adapted for printing amountsin a column on a work sheet and having a letter spacing carriage, aregister which is movable to difierent positions from a normally neutralposition for adding and subtracting, a unit on said carriage forcontrolling various functions of the machine, and a cycling generaloperator for running indexed amounts into the wheels of the register;the improvement comprising a state control means for determining whetherthe register is to be moved during a cycle from its neutral positioninto its adding or subtracting position, a spring-urged memberassociated with said state control means, an interlock between saidstate control means and said spring-urged member constructed andarranged to prevent operation of said spring-urged member at all timeswhen said state control means has not been moved to determine an addingor subtracting condition of the register, a normally effective lock forpreventing operation of said spring-urged member, said lock beingreleasable at only one predetermined letter space position in a column,and a sign printing train the operation of which is instituted by saidspring-urged member.

11. In a credit balance computing machine adapted for printing amountsin a column on a work sheet and having a letter spacing carriage, aregister which is movable to difierent positions from a normally neutralposition for adding and subtracting, a unit on said carriage forcontrolling various functions of the machine, and a cycling generaloperator for running indexed amounts into the register; the improvementcomprising a state control means for determining whether a register isto be moved during a cycle from its neutral position into its adding orsubtracting position, sensing means associated with the register forascertaining the clear condition thereof, an interlock between saidstate control means and said sensing means constructed and arranged toprevent operation of said sensing means at all times when said statecontrol means has not been moved to determine an adding or subtractingcondition of the register, a normally efiective lock for preventingoperation of said sensing means, said lock being releasable at only onepredetermined letter space position in a column, and a clear signprinting train the operation of which is instituted by said sensingmeans when said sensing means is allowed to operate and upon operationfinds the register to be clear.

12. In a credit balance computing machine adapted for printing amountsin a column on a Work sheet and having a letter spacing carriage, aregister which is movable to different positions from a normally neutralposition for adding and subtracting, a column unit on said carriage forcontrolling various functions of the machine, and a cycling generaloperator for running indexed amounts into the register; the improvementcomprising a fore-and-aft movable slide for determining whether aregister is to be moved during a cycle from its neutral position intoits adding or subtracting position, spring-operated sensing meansassociated with the register for ascertaining the clear conditionthereof, an interlock between said fore-and-aft movable slide and saidsensing means constructed and arranged to prevent operation of saidsensing means at all times when said fore-and-aft movable slide has notbeen moved to determine an adding or subtract- References Cited in thefile of this patent UNITED STATES PATENTS Number Name Date Hart Aug. 13,1918 Sohluns June 7, 1932 Schluns Oct. 4, 1938 Pitman Mar. 5, 1940

